Originally posted by ramanth

... and let water jet out of the hydrants for a good 10 minutes straight.

It was after dark. About 10 p.m.

The way the water was being released it was arching up
and falling right in front of my window like rain.

Why were they doing that? Relieving the pressure?


Good On the City!!

It's a form or Preventative Maintenance -
usually called "Flushing the Mains".

Water mains (pipes) build up sediment and other forms of crud
and the occasional dead critter that manage to get past
the filtration plants or crawl into a pipline when it's being built and
one end is "open" during the construction ...

"Flushing" allows a LOT of water to flow in the pipe - a LOT more than
normally moves when folks flush their toilets or take a shower -
the high flow rate "Flushes" the crud and sediment out of the pipes ...
and after what's left settles back down on the bottom of the pipe;
you get cleaner water.

The big RUB is the "flushing" REALLY Dirties up the water while it's being
done - and for a few hours AFTER the flow is shut down ...
NOT the thing to do on Clothes Washin Mondays!

Your City saves themselves a LOT of angry phone calls by doing it at night -
after the evening peak flow is over and at least some water users have
gone to bed! And hopefully what sediment remains in the lines
will settle out before morning when folks might notice it again.

The arching UP of the discharge?
An attempt to NOT cause damage by spreading out the flow and
dispersing it over a wider area. The flow from a Fire Hydrant, if
allowed to discharge onto a yard or even a street - is powerful
enough to dig HUGE Holes in your yard or even damage pavement.

Firefighters also do similar operations, opening one hydrant to take
"Flowing Pressure" measurements while another team takes
"Residual Pressure" measurements at another hydrant.
This data allows us to calculate just HOW Much water is available
from the water mains for use in firefighting operations.

Sounds like your City of Williamston is Right on the Ball with
taking care of "your" VERY Expensive water system!

/s/ Phred